I started with a Plan3D, made a polymesh, made a mask, extract it and them : issue
i think i read another post that says extractions are masked now for some reason, so try clear mask.
unfortunately , no changes
EDIT
You’re right in fact.
This is definitely something about masking but it seems wrong and messy. I fixed it but don’t know exactly what I fixed. I’ll try to find out why ! At least I hope so …